Do these magazines inflate their HP and torque

A lot depends on the dyno they used. As mentioned.. It is WELL known that some builders and magazines inflate, and it's more a function I believe of the calibrations on the dyno. Because it's all based on math, the variables on the setup can be manipulated to "fudge it". Similar to flow benches. They are just tools. Teh real test is the track. At a speed of 109, they are making steam. But the car is a package, like Guitar often says. If you compromise an area for something, like gearing for mileage, or wheels and tires for handling, you will lose something in anotehr area, like traction in a straight line. You cant have everything.